Conventionally flow meters for detecting the flow volume of a measurement fluid have been commercialized. In order to obtain accurate measurements of the flow volume using this type of flow meter, it has been necessary to stabilize the distribution of the speed by controlling turbulence in the measurement fluid flowing through the flow path.
Because of this, at present there are proposals for technologies for controlling the turbulence in the measurement fluid that flows to the flow path through the provision of a plurality of flow rectifying plates in the flow path of the flow meter. (See, for example, Japanese Unexamined Patent Application Publication 2005-24080 (“JP '080”).) Additionally, in recent years there have been proposals for technologies for stabilizing the speed distribution of the fluid through causing the fluid to impinge upon an inner wall of the flow path, through the provision of a plurality of curved portions in the flow path. (See, for example, Patent References 2 and 3 International Patent Application Publication 2005/121718 (“JP '718”) and Japanese Unexamined Patent Application Publication 2007-121036 (“JP '036”).)
However, when the technology as described in JP '080 is used, conventional flow rectifying plates are disposed so as to be perpendicular to the direction in which the flow path extends, and thus there is a problem in that this increases the loss of pressure in the measurement fluid. Additionally, even when the technologies described in JP '718 and JP '036 are used, there is still the danger of an increase in the pressure loss in the measurement fluid due to the many curved portions that are provided in order to obtain a repeatable and uniform flow speed distribution.
The present invention is the result of contemplation on this situation, and the object thereof is to provide a flow meter and a flow volume controlling device equipped therewith, capable of obtaining a flow rectifying effect in the measurement fluid while preventing an increase in pressure loss.